DURHAM, N.C. — The prosecution in the Mike Peterson case is trying to pick apart the testimony of a well-known forensic scientist. Dr. Henry Lee returned to the stand for a second day in a row.

Kathleen Peterson was found dead at the bottom of a stairwell at her home on Dec. 9, 2001. Mike Peterson is charged in the death of his wife. Lee, who is known for his work in several high-profile trial like the O.J. Simpson trial, said blood spatter found in the stairwell is the result of Kathleen Peterson's own actions.

"These medium-velocity patterns can be produced by coughing, sneezing, breathing, movement of the hair," Lee said.

District Attorney Jim Hardin tried to get Lee to back down from his findings.

"You can't exclude that she was beaten," Hardin said.

"Nobody can exclude everything," Lee responded.

Lee said there was too much blood spatter to suggest that Kathleen Peterson was beaten to death.

Prosecutors claims blood spatter found inside Mike Peterson's shorts place him at the scene at the time of Kathleen Peterson's death. Lee said the blood found on Mike Peterson's shorts could have come from Kathleen Peterson coughing on him.

Lee also criticized tests done by Peter Duane Deaver, the state's blood spatter expert calling them child's play.

"It's doesn't matter how many tests you do. You're not going to produce the same scene because this is a dynamic situation," he said. "You can jump. You can beat a mannequin head. That's not real-life."

Hardin also reminded Lee that last year he actually complimented Deaver. Hardin had Lee read a book inscription he had written to Deaver.

"To Duane Deaver, one of the best, keep up your good work," Lee wrote.

Lee said he wrote that to be polite and that he has probably inscribed thousands of other books the same way.

On Wednesday, a biomechanics expert is expected to take the stand to explain how Kathleen Peterson could have fallen to her death.

Defense attorney David Rudolf said there is a possibility that he may be able to wrap up his case by Friday.